Spatial audio signals are being used in greater frequency to produce a more immersive audio experience. A stereo or multi-channel recording can be passed from the recording or capture apparatus to a listening apparatus and replayed using a suitable multi-channel output such as a pair of headphones, headset, multi-channel loudspeaker arrangement etc.
Object oriented audio formats represent audio as separate tracks with trajectories. The trajectories contain the directions from which the audio on the track should sound to be coming from during playback. These trajectories are typically expressed with polar coordinates, where the polar angle and azimuth provide the direction.
Several object oriented audio formats have been presented, e.g. Dolby Atmos, MPEG SAOC. Object oriented audio formats have several benefits. For the consumer the most important benefit is the ability to play back the audio using any equipment and still achieve improved audio quality unlike when fixed 5.1 multichannel audio signals are downmixed or the like are used on playback equipment which has fewer channels than the audio signals or when fixed 5.1 multichannel audio signals are upmixed or the like are used on playback equipment which has more channels than the audio signals. The playback equipment can for example be headphones, 5.1 surround in a home theatre apparatus, mono/stereo speakers in a television or a mobile device.
However it would be understood that such object oriented representations can be problematic. The format known as Dolby Atmos can use up to 200 individual channels. Due to data transfer and computational limitations, attempting to transmit store or render 200 channels can impose a significant bandwidth and processing load. This bandwidth and processing load can be significant for mobile devices requiring additional processing capacity with cost and power usage disadvantages. Furthermore a fixed 5.1 downmix would lose all the benefits from an object oriented audio format, such as high quality with any loudspeaker or headphone setup and the possibility to play back audio from above or below.